#include<stdio.h>
#include<sys/types.h>
#include<unistd.h>
#include<stdlib.h>
int main()
{
    printf("exec command begin,pid:%d\n",getpid());   
    execl("/usr/bin/ls","ls","-a","-l",NULL);
    printf("exec command end,pid:%d\n",getpid());

    exit(1);
}
